// 将elm插入parent下,如果传入ref则插入到ref前
function insert (parant, elm, ref) { }

function createElm (vnode, parentElm, refElm) { }

function addVnodes (params) {

}

function removeNode (params) {

}

function removeNodes (params) {

}

function patch (oldVnode, vnode, parentElm) {
  
  if (!oldVnode) {
    
  }

}